Add Subject Validation

Add vim artifacts to .gitignore

Add more validations + specs
Merge pull request #3 from samsheff/feature/add-issue-validations

Write model validation logic for issues - #66
Add Client Specs
Add Project Specs
Merge pull request #6 from samsheff/feature/project_specs

Write Unit Tests for Projects #37
Merge pull request #5 from samsheff/feature/client_specs

Write Unit Tests for Clients #29